Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 161ac679bc616f28…

MALICIOUS

Office (OLE) / .XLS

77.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-24
MD5: a66b8f31a7df02f14d59d5be4db721a0 SHA-1: 31c9194a674186785f8c1d73790a5e559cb7bd66 SHA-256: 161ac679bc616f284683019e75bff26c77cf7e53a7aac8447f5131c74592ca5d
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry point, which is a known technique for executing malicious code. The macro sheet contains references to dangerous formula APIs, specifically the RUN function, suggesting it is designed to execute external commands or download payloads. The extracted URLs are likely part of this payload delivery mechanism.

Heuristics 3

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
2ca0966e93dacad101ceb18f4d58731b5432892fe851526f2fda59486181312c
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7325 bytes